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Post by Tabpat on May 1, 2005 21:43:46 GMT -5
The Passport exhaust can be made to fit the NP50T-M. I have a 100cc engine on mine and it has been problematic from the start. It would backfire whenever I would go 40mph or faster, then let go of the throttle (i.e. going down hills). Looking at the original tailpipe, I wondered if the small header pipe was the cause - so I bought the canister exhaust pipe for a Passport from Beatrice Cycle www.dratv.com/ online. I had to fabricate a metal hanger bracket and slightly offset one of the mounting flange bolt holes, but it works. The backfire problem is now gone. Mid-range accelleration is improved and there is more power on the top end. It is almost as quiet as the stock pipe. The header pipe is a full 10mm larger than the stock exhaust.
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Post by aeholton on May 2, 2005 8:29:34 GMT -5
Looks nice. Did you order your bike w/ the 100cc engine, or install it after you got it?
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Post by Tabpat on May 2, 2005 9:00:00 GMT -5
It came with the 70cc...err...50cc engine. I added the 100cc 6 months later. I think all of the "50cc Jialings" have the cheater cylinder on them, which makes them a 70cc (but the cylinder is maked as a 48ccm). The bike isn't that much faster than the stock engine, but it has a lot more pull. On a flat road, I hit 52mph with the new exhaust (up from 48mph). That's with stock gearing. I need to change my front sprocket for this to work right.
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Post by aeholton on May 2, 2005 14:16:07 GMT -5
Did you do an entire engine swap out or just change head, piston,...etc.? Where did you get it? What did you pay?
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Post by Tabpat on May 2, 2005 14:29:58 GMT -5
It was a complete engine. This is the "auto-clutch" version. I think it was around $500...but they have come down. I got it from "wholesalepricebusters," but they have moved and changed names. That engine is a torquey beast, though. No need for 1st gear.
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Post by Feo on May 4, 2005 16:43:30 GMT -5
Does that mean if we order one of these bikes from Sig and decide to put on one of his 100cc engines, that we are also going to have to fit a different exhaust system on it too ?
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Post by Tabpat on May 5, 2005 9:38:05 GMT -5
You don't have too...but you will have to heat the stock pipe header to conform to slightly elongated cylinder, and enlarge the bolt hole in the bracket so the mufler can move foward a bit. The stock muffler is way too restrictive, though.
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Post by Tabpat on May 7, 2005 21:11:05 GMT -5
Today, I swapped the front sprocket to a 16th, up from the 13th. I have swapped them before, but the bike would actually slow down in 4th gear instead of go faster...or at least maintain the speed. It didn't have enough power. However, with the new exhaust the performance is way up. It hit 59mph on a fairly flat road. The fastest this bike ever hit with the old exhaust was 53mph. Even though this is anectdotal information, I know the bike is much faster and breathes better. There isn't a hint that the bike wants to slow down in 4th, either. I tried it on hills and it feels like it can pull tree stumps out of the ground. I have yet to hear that backfire, too!
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Post by EJ on May 7, 2005 23:02:45 GMT -5
59mph . Sounds sweet man! How was the acceleration affected after swapping to the 16 tooth sprocket?
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Post by Tabpat on May 7, 2005 23:27:50 GMT -5
It accelerates great. I think the added draw on the low end that the larger front pulley made is really not noticeable since there is so much torgue.
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Post by rastoga on May 8, 2005 22:15:57 GMT -5
Where did you get the 16 tooth sprocket from?
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Post by Tabpat on May 9, 2005 9:22:21 GMT -5
You can find them in a lot of places, but I think I got this one at hondaminitrail.com.
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Post by Tabpat on May 10, 2005 21:38:52 GMT -5
One other thing and I'll shuddup about this. Before the muffler swap, I was getting around 60mpg. After the muffler swap, the mileage jumped to 100mpg. That alone should tell you something about the restrictiveness of the stock tailpipe. Almost 2x the mpg!!
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Post by aeholton on May 11, 2005 14:33:32 GMT -5
Tabpat - Did you install a new speedo? How are you clocking your speed beyond 50mph?
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Post by Tabpat on May 11, 2005 23:10:46 GMT -5
I have a cyclometer on it. That was the first thing I installed when I got the bike.
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